Effects of Statin and Ezetimibe Association on Kinetics of Artificial Chilomicrons

Effects of statin and ezetimibe association on kinetics of artificial chylomicrons in men with stable coronary heart disease (CHD). Background: The rate (kinetics) of chylomicrons removal from circulation have been correlated with the incidence and severity of atherosclerotic lesions; a number of studies demonstrated lower plasmatic clearance of chylomicrons in patients with CHD compared to patients without this condition. It was also demonstrated a correlation among LDL-C levels and removal of chylomicrons remnants by a technique employing artificial chylomicrons. The investigators also know that higher doses of more potent statins are more effective in chylomicrons removal than lower doses or less potent statins; nevertheless, the effect of the isolated use of statin has not been completely studied up to now. Study design: The investigators propose to study 26 outpatients volunteers with chronic CHD, followed at the Heart Institute - INCOR - of the School of Medicine, University of São Paulo. Following a period of six weeks of washout from any cholesterol reducer, the kinetics of chylomicrons removal by a technique of emulsion of radiolabeled artificial chylomicrons will be evaluated. Lipid fractions, hepatic enzymes and CK will be measured. Initially patients will be randomly allocated to receive simvastatin 20 mg /day (n= 13) or ezetimibe 10 mg/day (n=13) for six weeks. At the end of this period, kinetics of chylomicrons removal and laboratorial measurements will be repeated (Period 1). In the next period (Period 2) patients will receive simvastatin 20 mg/ ezetimibe 10 mg (n=13) or simvastatin 80 mg (n=13) for additional six weeks; at the end of this period, the evaluations will be repeated (third and last evaluation). The aim of this study is to further understand chylomicrons metabolism in patients with chronic coronary disease receiving cholesterol reducers at different dosage regimes.